Along with the development of the mobile communication technology, the mobile communication terminal has been much popularized as a popular consumer product. The SIM (Subscriber Identity Model) card, as an important part of the mobile communication terminal, is broadly used. To satisfy the continuously increasing use experiences of the people for mobile communication terminals, a SIM card with multiple new functions is developed and is put into use. A radio-frequency SIM card with low-frequency magnetic communication is one of the examples.
The radio-frequency SIM card with low-frequency magnetic communication is a SIM card with functions of radio-frequency communication, low-frequency magnetic communication, and low-frequency magnetic induction intensity detection. It comprises a card body and an integrated circuit in the card body. The card body of the radio-frequency SIM card comprises a SIM card interface that matches with a mobile phone. The integrated circuit in the card body comprises: a central processing unit (CPU); a SIM card memory, a radio-frequency transceiver circuit, and an interface circuit that are electrically connected with the CPU, respectively; and a radio-frequency transceiver antenna electrically connected with the radio-frequency transceiver circuit. The radio-frequency SIM card not only can communicate with the mobile communication terminal to realize functions of a normal SIM card but also can conduct short-distance communication with matching external processing devices (e.g. a card reader) through the radio-frequency transceiver circuit and interface circuit. The communication process and content is processed specifically by the central processing unit CPU inside the radio-frequency SIM card.
The radio-frequency SIM card with low-frequency magnetic communication is mostly used in a mobile phone. Besides all the functions of a normal SIM card, it can also allow the mobile phone to have functions of smart cards such as a public transit card, an entrance guard communication card, a credit card, a small-amount payment card, and a time card. Moreover, the information generated when the various smart card functions are used can be displayed directly on a screen of the mobile phone and the user can accomplish the various operations through a keyboard of the mobile phone.
When a radio-frequency SIM card with low-frequency magnetic communication is used as smart cards such as a public transit card, an entrance guard communication card, a credit card, a small-amount payment card, and a time card, the working principle is as follows: between the card reader and the radio-frequency SIM card, a transaction distance control is implemented through a low-frequency channel and a transaction is conducted through the radio-frequency channel. The short-distance communication process between the card reader and the radio-frequency SIM card is as follows: the card reader transmits a low-frequency signal, and the radio-frequency SIM card receives this low-frequency signal and examines its intensity. If the intensity of the low-frequency signal received by the radio-frequency SIM card reaches a preset threshold value, it indicates that the radio-frequency SIM card has entered the transaction scope of the card reader and a transaction is allowed. Now the radio-frequency communication part of the radio-frequency SIM card is activated, and the radio-frequency SIM card carries out the transaction with the card reader through the radio-frequency channel. If the intensity of the low-frequency signal received by the radio-frequency SIM card does not reach the preset threshold value, it indicates that the radio-frequency SIM card has not entered the transaction scope of the card reader and the transaction is not allowed. Now the radio-frequency communication part of the radio-frequency SIM card is not activated, and the radio-frequency SIM card can not establish a connection of the radio-frequency channel with the card reader.
To avoid a misreading operation, the radio-frequency SIM card needs to enter a certain scope of the card reader to trigger the transaction function. With the low-frequency magnetic induction intensity detection, the distance between different types of mobile communication terminals and the card reader can be controlled effectively within a certain scope. Moreover, in typical radio-frequency SIM card applications, when the radio-frequency SIM card is used as a kind of identification or a small-amount payment tool, to increase the application convenience, the transaction result is normally not displayed on a screen of the mobile communication terminal for the user to confirm.
In the existing short-distance communication system of a radio-frequency SIM card with low-frequency magnetic communication, if two or more radio-frequency SIM cards exist within a transaction scope (also referred to as a card swiping scope in this application), the card reader will randomly connect with either of them to conduct a transaction. In this case, we find that when two or more radio-frequency SIM cards exist concurrently within the transaction scope, one of the radio-frequency SIM cards will be transacted firstly but the user cannot determine which one is transacted.
In another case, the existing low-frequency magnetic communication card reader transmits characteristic information to a radio-frequency SIM card through a low-frequency channel and realizes the unique binding between the radio-frequency SIM card and the card reader through the characteristic information. However, the physical properties of the low-frequency channel decide that its data transmission rate cannot be very high. Therefore, it is impossible to transmit too much low-frequency card reader identification information through the low-frequency channel. When multiple card readers with low-frequency magnetic communication exist in a scope of a same scene (e.g. a subway gate, a supermarket payment exit, etc.), their low-frequency card seeking characteristic information may repeat. When the characteristic information repeats, if the radio-frequency SIM card with low-frequency magnetic communication is activated on a card reader, its radio-frequency channel may communicate with another adjacent card reader that transmits the same low-frequency characteristic information.
The above two situations are uncertain transaction processes caused by the concurrent existence of multiple card readers and multiple radio-frequency SIM cards. We define such a kind of uncertain transactions as a radio-frequency SIM card collision, and define the zone where such uncertain transactions may appear as a radio-frequency SIM card transaction collision zone. The generation of the collision brings certain hidden dangers to the safety and reliability of a radio-frequency SIM card transaction.
One method for resolving the above problem is to display the transaction information on the mobile communication terminal during the transaction for the user to confirm. However, this method sacrifices the use convenience. Therefore, how to avoid the hidden dangers to the safety and reliability of the radio-frequency SIM card transaction without sacrificing the use convenience is a problem to be resolved.